I am working on a drawing that I am trying to REV UP but am being blocked by the following error message:

I have limited knowledge of the PDM software but can almost pin-point the cause of this issue.  We were in the process of upgrading to SW2018 when we had learned that our server was too old to be supportive of SW2018.  In the meantime, I began making designs, drawings, changes, etc in SW2018.  Upon realizing that this will be an issue (including being unable to update our PDM to 2018), we reverted back to SW2017, as well as the PDM software.

Now, I need to revise a drawing (bump it up a revision level) that I had created in 2018, but get the above error message.  I was gonna do an "Edit Sheet" and update the Rev variable and add my revision notes but I am trying to think about down the road, when we need to revise this drawing again.  Seeing how I am trying to perform a task in 2018 that is being controlled by a 2017-version of PDM is, more than likely, the culprit.

Does anyone know anything about this or do I need to "cheat" SW as described? Sorry for the lack of knowledge and proper terminology for all of this.  Again, I know the basics and that's about all.

Any and ALL help will be greatly appreciated.

Thanks!